JP3897428B2 - One-part moisture-curing urethane sealant composition - Google Patents

Description

【０００８】
（式中、ｍは０又は１である）で表わされるジモルフォリノジエチルエーテル化合物及び（ii）シーラント組成物中の含量が０．０５〜２重量％のＮ−（Ｎ′，Ｎ′−ジメチルアミノエチル）モルフォリン並びに
（ｃ）シーラント組成物中の含量が２〜２０重量％の、平均粒子径が１．０〜３．２μｍの重質炭酸カルシウムを含んでなる一液湿気硬化型ウレタン組成物
が提供される。
【０００９】
【発明の実施の形態】
本発明によれば、前述の如く、ポリエーテルトリオールとポリエーテルジオールとの混合物に硬化性に優れたイソシアナート化合物として４，４′−ジフェニルメタンジイソシアナートをＮＣＯ基／ＯＨ基の当量比が１．１〜２．５になるように反応させたウレタンプレポリマーと、深部硬化性を付与するために平均粒子径が１．０〜３．２μｍの重質炭酸カルシウムをシーラント組成物中に２〜２０重量％、好ましくは３〜１５重量％配合し、更に触媒として、（ｉ）前記式（Ｉ）のジモルフォリノジエチルエーテル化合物をシーラント組成物中に０．０５重量％以上０．１５重量％未満、好ましくは０．０８〜０．１４重量％、更に好ましくは０．０９〜０．１３重量％及び（ii）シーラント組成物中の含量が０．０５〜２重量％、好ましくは０．０５〜１重量％、更に好ましくは０．０５〜０．７重量％のＮ−（Ｎ′，Ｎ′−ジメチルアミノエチル）モルフォリンを配合することにより高温多湿環境下でもプライマーとの充分な接着性を有し、貯蔵安定性に優れ、充分な硬化性を有した湿気硬化型ウレタンシーラントを得ることができると共に、硬化環境の変化による接着性の不良の問題を生じないことを見出した。
【００１０】
本発明のシーラント組成物に配合するウレタンプレポリマーは公知の物質であり、例えば一分子当り３個の水酸基を有する、数平均分子量約５０００のポリオキシプロピレントリオールなどのポリエーテルトリオールと、一分子当り２個の水酸基を有する数平均分子量約２０００のポリプロピレンエーテルジオールなどのポリエーテルジオールとの混合物に、４，４′−ジフェニルメタンジイソシアネートを反応させて所望のウレタンプレポリマーを得ることができる。
【００１１】
本発明において用いる第一の硬化触媒は前記式（Ｉ）で表わされるジモルフォリノジエチルエーテル化合物であり、かかる化合物も例えば前述の特公平５−７５０３５号公報や特公平７−８９８２号公報などに表記載される通り公知である。この触媒の配合量はシーラント組成物重量当り０．０５重量％以上０．１５重量％未満、好ましくは０．０８〜０．１４重量％であり、配合量が少な過ぎると充分な硬化性が得られないので好ましくなく、逆に多過ぎると硬化環境が変化した時、特に高温高湿下で硬化させた時にプライマー／シーラント間で界面剥離を生じるおそれがあるので好ましくない。
【００１２】
本発明において第二の硬化触媒として用いるＮ−（Ｎ′，Ｎ′−ジメチルアミノエチル）モルフォリンは下記式（II）で表わされる化合物であり、この化合物は公知で市販のものを使用することができる。
【００１３】
【化３】

【００１４】
Ｎ−（Ｎ′，Ｎ′−ジメチルアミノエチル）モルフォリンの配合量はシーラント組成物重量当り０．０５〜２重量％、好ましくは０．０５〜１重量％であり、この配合量が少な過ぎると硬化時間を調整するためにジモルフォリノ化合物量が増えるため、高温高湿下でプライマー／シーラント間で界面剥離を生じるおそれがあり、逆に多過ぎると貯蔵安定後に塗布したシーラントの形状維持性が落ちるので好ましくない。
【００１５】
本発明に従えば、前述の如く、シーラント組成物中に、平均粒径が１．０〜３．２μｍの重質炭酸カルシウムを２〜２０重量％、好ましくは３〜１５重量％を配合する。
【００１６】
重質炭酸カルシウムの平均粒子径が１．０μｍ未満では、湿分不在化での貯蔵安定性が悪くなり、また３．２μｍを超えるとシーラントの外観に平滑性を損なうことがあって好ましくない。本発明に従って、重質炭酸カルシウムを配合すると前述の如く、いわゆる「深部硬化性」を付与するので好ましい。ここで深部硬化性とは、湿分下において材料が時間に対して形成される膜の厚さで示される速度をいう。
【００１７】
本発明の組成物には、所望の物性等を付与するために、この他、イソシアネート基に対して不活性な充填剤、可塑剤、溶剤等を含有せしめることができる。例えば、充填剤としては、カーボンブラック、クレー、タルクなど又はこれらの混合物が挙げられ、可塑剤としては、ジプチルフタレート、ジオクチルフタレート等のフタル酸誘導体をはじめ、テトラヒドロフタル酸、アゼライン酸、マレイン酸、トリメリット酸、イソフタール酸、アジピン酸、イタコン酸、クエン酸等の誘導体が、溶剤としては、トルエン、キシレン等の芳香族炭化水素系溶剤等が例示される。
【００１８】
本発明のシーラント組成物の製造方法には、特に限定はないが、硬化触媒および溶剤を除く各成分を減圧下に充分混練し、均一に分散した後、硬化触媒をキシレン等の溶媒に溶かして加え、減圧下にさらに充分混練して組成物とするのが良い。
【００１９】
【実施例】
以下、実施例により本発明を更に具体的に説明するが、本発明をこれらの実施例に限定するものでないことはいうまでもない。
【００２０】
実施例１〜２及び比較例１〜４
ポリエーテルトリオール平均分子量約５０００とポリエーテルジオール平均分子量約２０００を重量比６／４で混合し１１０℃で脱水後、溶融した４，４′−ジフェニルメタンジイソシアネートをＮＣＯ基／ＯＨ基のと当量比１．７になる量を加え８０℃窒素置換中で３６時間混合撹拌後、プレポリマー（Ａ）を得た。このようにして得られたプレポリマー（Ａ）にプレポリマー１００重量部当り可塑剤としてジオクチルフタレート３０重量部、カーボンブラック７０重量部、重質炭酸カルシウム（平均粒子径２．０μｍ）３０重量部を添加し真空下でミキサーで１時間混合後、触媒と安定剤としてジエチルマロネートを投入してさらに１０分間混合しシーラント予備組成物を得た。
【００２１】
表Ｉに示すように、触媒としてジモルフォリノジエチルエーテル（ＤＭＤＥＥ）（ハンツマン社製）及びＮ−（Ｎ′，Ｎ′−ジメチルアミノエチル）モルフォリンを表Ｉに示す配合量で配合してシーラント組成物を得、それらの高温高湿硬化性及び垂下性を測定した。結果を表Ｉに示す。
【００２２】
【表１】

【００２３】
＊１：高温高湿時の硬化試験評価
被着体（プライマーを塗布したガラス等）にシーラント組成物を塗布し、２０℃及び６０％相対湿度（ＲＨ）下で３時間置いた後、４０℃の温水中で硬化（２４時間）させる。これを１８０°剥離させて、その破壊状況を観察する。
評価：ＣＦ＝シーラントの凝集破壊、
ＰＳ＝プライマー／シーラント間の界面剥離
【００２４】
＊２：垂下性試験
塗布したシーラントの形状維持性の評価方法として垂下性試験がある。ガラス板にシーラント組成物を底辺６mm、高さ１０mmの直角三角形ビードで帯状に押し出す（図１）。押し出し後、直ちに試験板に保持具を取り付け９０°の角度に保持し（図２）、２０±２℃、６５％ＲＨで３０分間放置後の試料の頂点の移行距離及びたれ下がりの距離ｈを測定する（図３）。測定後、最大距離を表示する。
ｈ＜２mmの場合 良好（○）
ｈ≧２mmの場合 不良（×）
【００２５】
以上の通り、本発明のウレタンシーラント組成物はジモルフォリノジエチルエーテル化合物及びＮ−（Ｎ′，Ｎ′−ジメチルアミノエチル）モルフォリンを触媒として特定量配合することにより硬化環境が変化した場合にも接着不良などの問題を引き起すことなく良好な接着性を得ることができる。
【図面の簡単な説明】
【図１】本発明の実施例及び比較例の垂下性試験において、塗布した試料を正面からみた所で、塗布シーラントの長さは１００mmである。
【図２】本発明の実施例及び比較例の垂下性試験において、塗布したシーラントを横からみた図でシーラントの断面の様子を示す。
【図３】本発明の実施例及び比較例の垂下性試験においてたれ下がりの距離ｈ（mm）の測定方法を示す図面である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a one-component moisture-curing urethane sealant composition used as a sealing agent, an adhesive and a coating agent for automobiles, buildings and structures. More specifically, the present invention relates to a high curing rate and during accelerated curing with a catalyst. There is no adhesion failure, excellent storage stability in the absence of moisture, and sufficient curability can be obtained in atmospheric moisture, while maintaining adhesion under changing curing conditions, shape after application of sealant The present invention relates to a one-component moisture-curing urethane sealant composition that has no problem in maintainability.
[0002]
[Prior art]
Conventionally, various urethane compositions utilizing moisture curing have been proposed. In the field of automobiles, such as bonding between a vehicle body and a window glass, or in the construction field, and further, for example, structural bonding for bonding metals together. As an agent, it is used in many fields. The moisture curable urethane composition is usually blended with a tertiary amine-based and / or carboxylic acid metal salt-based curing catalyst, and the curing rate is adjusted by selecting the type and blending amount.
[0003]
On the other hand, in view of storage stability and sufficient curability, it has been proposed in JP-B-5-75035 that dimophorinodiethyl ether (DMDEE) is blended as a curing catalyst for urethane prepolymer. The use of a certain di [2- (3,5-dimethylmorpholino) ethyl] ether as a catalyst has also been proposed in Japanese Examined Patent Publication No. 7-8982.
[0004]
[Problems to be solved by the invention]
However, the present inventors have found that dimorpholinodiethyl ether compounds are effective as catalysts having storage stability in the absence of moisture and sufficient curability in the presence of moisture in the atmosphere. If changed, there was a problem in adhesiveness, and there was a possibility that, for example, interfacial peeling occurred between the primer.
[0005]
Therefore, the present invention uses dimorpholinodiethyl ether or a derivative thereof as a catalyst to solve the problem of adhesion failure at the time of accelerated curing, and also has good storage stability and is sufficiently cured by moisture in the atmosphere. An object of the present invention is to provide a one-component moisture-curing urethane sealant composition that does not adversely affect its adhesiveness even when the curing environment changes.
[0006]
[Means for Solving the Problems]
According to the present invention,
(A) In a mixture of polyether triol having a number average molecular weight of 1000 to 7000 and polyether diol, 4,4'-diphenylmethane diisocyanate has an NCO group / OH group equivalent ratio of 1.1 to 2.5. Urethane prepolymer reacted to be
(B) As a catalyst, the content in the (i) sealant composition is 0.05% by weight or more and less than 0.15% by weight, formula (I):
[0007]
[Chemical 2]

[0008]
(Wherein m is 0 or 1) and (ii) N- (N ′, N′-dimethyl ) having a content of 0.05 to 2% by weight in the sealant composition (Aminoethyl ) morpholine and (c) a one-component moisture-curing urethane composition comprising heavy calcium carbonate having an average particle size of 1.0 to 3.2 μm and having a content of 2 to 20% by weight in the sealant composition Things are provided.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
According to the present invention, as described above, 4,4′-diphenylmethane diisocyanate is an NCO group / OH group equivalent ratio of 1 as an isocyanate compound having excellent curability in a mixture of polyether triol and polyether diol. In the sealant composition, a urethane prepolymer reacted so as to be 1 to 2.5 and heavy calcium carbonate having an average particle diameter of 1.0 to 3.2 μm in order to impart deep curability to the sealant composition. 20% by weight, preferably 3 to 15% by weight, and further, as a catalyst, (i) the dimorpholino diethyl ether compound of formula (I) is 0.05% by weight or more and 0.15% by weight in the sealant composition. Less than, preferably 0.08 to 0.14% by weight, more preferably 0.09 to 0.13% by weight and (ii) a content in the sealant composition of 0.05 to 2% by weight, preferably Or 0.05 to 1% by weight, more preferably 0.05 to 0.7% by weight of N- (N ′, N′-dimethylaminoethyl) morpholine is added to the primer even in a hot and humid environment. It is possible to obtain a moisture-curing urethane sealant having sufficient adhesive properties, excellent storage stability, and sufficient curability, and not causing the problem of poor adhesion due to changes in the curing environment. I found it.
[0010]
The urethane prepolymer blended in the sealant composition of the present invention is a known substance, for example, a polyether triol having a number average molecular weight of about 5000 having 3 hydroxyl groups per molecule and a per molecule. A desired urethane prepolymer can be obtained by reacting a mixture with a polyether diol such as polypropylene ether diol having two hydroxyl groups and a number average molecular weight of about 2000, with 4,4'-diphenylmethane diisocyanate.
[0011]
The first curing catalyst used in the present invention is a dimorpholinodiethyl ether compound represented by the above formula (I), and such a compound is also disclosed in, for example, the above-mentioned Japanese Patent Publication No. 5-75035 and Japanese Patent Publication No. 7-8982. Known as listed. The blending amount of this catalyst is 0.05% by weight or more and less than 0.15% by weight, preferably 0.08 to 0.14% by weight, based on the weight of the sealant composition. If the blending amount is too small, sufficient curability can be obtained. On the other hand, when the curing environment changes, particularly when curing is performed under high temperature and high humidity, interfacial peeling may occur between the primer and the sealant.
[0012]
N- (N ′, N′-dimethylaminoethyl) morpholine used as the second curing catalyst in the present invention is a compound represented by the following formula (II), and this compound should be a known and commercially available compound. Can do.
[0013]
[Chemical 3]

[0014]
The amount of N- (N ′, N′-dimethylaminoethyl) morpholine is 0.05 to 2% by weight, preferably 0.05 to 1% by weight, based on the weight of the sealant composition, and this amount is too small. Since the amount of dimorpholino compound increases to adjust the curing time, there is a risk of interfacial delamination between the primer and sealant at high temperature and high humidity. Therefore, it is not preferable.
[0015]
According to the present invention, as described above, 2 to 20% by weight, preferably 3 to 15% by weight of heavy calcium carbonate having an average particle diameter of 1.0 to 3.2 μm is blended in the sealant composition.
[0016]
If the average particle size of the heavy calcium carbonate is less than 1.0 μm, the storage stability in the absence of moisture is deteriorated, and if it exceeds 3.2 μm, the smoothness of the sealant is impaired, which is not preferable. In accordance with the present invention, it is preferable to add heavy calcium carbonate since it imparts so-called “deep curability” as described above. Here, the deep curability refers to a speed indicated by a thickness of a film in which a material is formed with respect to time under moisture.
[0017]
In addition to the above, the composition of the present invention may contain a filler, a plasticizer, a solvent and the like which are inert to the isocyanate group in order to impart desired physical properties. For example, examples of the filler include carbon black, clay, talc, and the like, and mixtures thereof. Examples of the plasticizer include phthalic acid derivatives such as diptyl phthalate and dioctyl phthalate, tetrahydrophthalic acid, azelaic acid, and maleic acid. Derivatives such as trimellitic acid, isophthalic acid, adipic acid, itaconic acid and citric acid, and examples of the solvent include aromatic hydrocarbon solvents such as toluene and xylene.
[0018]
The method for producing the sealant composition of the present invention is not particularly limited, but each component except the curing catalyst and the solvent is sufficiently kneaded under reduced pressure and uniformly dispersed, and then the curing catalyst is dissolved in a solvent such as xylene. In addition, the composition is preferably kneaded sufficiently under reduced pressure.
[0019]
【Example】
EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but it goes without saying that the present invention is not limited to these examples.
[0020]
Examples 1-2 and Comparative Examples 1-4
A polyether triol average molecular weight of about 5000 and a polyether diol average molecular weight of about 2000 were mixed at a weight ratio of 6/4, dehydrated at 110 ° C., and melted 4,4′-diphenylmethane diisocyanate with an NCO group / OH group equivalent ratio of 1 Was added and mixed and stirred for 36 hours in a nitrogen atmosphere at 80 ° C., and then a prepolymer (A) was obtained. 30 parts by weight of dioctyl phthalate, 70 parts by weight of carbon black and 30 parts by weight of heavy calcium carbonate (average particle size 2.0 μm) as a plasticizer per 100 parts by weight of the prepolymer were added to the prepolymer (A) thus obtained. After adding and mixing for 1 hour in a mixer under vacuum, the catalyst and diethyl malonate as a stabilizer were added and further mixed for 10 minutes to obtain a sealant preliminary composition.
[0021]
As shown in Table I, dimorpholinodiethyl ether (DMDEE) (manufactured by Huntsman) and N- (N ′, N′-dimethylaminoethyl) morpholine as the catalyst were blended in the blending amounts shown in Table I and the sealant. Compositions were obtained and their high temperature and high humidity curability and sag were measured. The results are shown in Table I.
[0022]
[Table 1]

[0023]
* 1: Curing test evaluation at high temperature and high humidity After applying the sealant composition to an adherend (eg, glass coated with a primer) and placing it under 20 ° C. and 60% relative humidity (RH) for 3 hours, 40 ° C. Cured in warm water (24 hours). This is peeled 180 ° and the state of destruction is observed.
Evaluation: CF = cohesive failure of sealant,
PS = Interfacial debonding between primer / sealant [0024]
* 2: Droopability test There is a drooping test as a method for evaluating the shape maintenance of the applied sealant. The sealant composition is extruded into a glass plate with a right triangle bead having a base of 6 mm and a height of 10 mm (FIG. 1). Immediately after extrusion, a holder is attached to the test plate and held at an angle of 90 ° (FIG. 2), and the vertex transition distance and sagging distance h after being left at 20 ± 2 ° C. and 65% RH for 30 minutes. Measure (Figure 3). After measurement, the maximum distance is displayed.
Good when h <2mm (○)
When h ≧ 2mm, defective (×)
[0025]
As described above, the urethane sealant composition of the present invention is used when the curing environment is changed by blending a specific amount of dimorpholinodiethyl ether compound and N- (N ′, N′-dimethylaminoethyl) morpholine as a catalyst. Also, good adhesiveness can be obtained without causing problems such as poor adhesion.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 shows a coating sealant with a length of 100 mm when a coated sample is viewed from the front in a sag test of examples and comparative examples of the present invention.
FIG. 2 shows a cross-sectional view of a sealant as seen from the side in a drooping test of an example of the present invention and a comparative example.
FIG. 3 is a drawing showing a method for measuring a hung distance h (mm) in a drooping test of an example of the present invention and a comparative example.

Claims (1)

(A) In a mixture of polyether triol having a number average molecular weight of 1000 to 7000 and polyether diol, 4,4'-diphenylmethane diisocyanate has an NCO group / OH group equivalent ratio of 1.1 to 2.5. Urethane prepolymer reacted to be
(B) As a catalyst, the content in the sealant composition (i) is 0.05% by weight or more and less than 0.15% by weight, formula (I):

(Wherein n is 0 or 1) and (ii) N- (N ′, N′-dimethyl ) having a content in the sealant composition of 0.05 to 2% by weight (Aminoethyl ) morpholine and (c) a one-component moisture-curing urethane composition comprising heavy calcium carbonate having an average particle size of 1.0 to 3.2 μm and a content of 2 to 20% by weight in the sealant composition object.

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